Drafting instrument



No. 6|4,985. Patented Nov. 29, |398.v

R. HUFFIN.- DBAFTING INSTRUMENT.

(Application led Aug. 18. 1897.)

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No. 64,985. Patented Nov. 29, |898. R. RUFFIN.

DRAFTING INSTRUMENT.

(Application Bled Aug'. 1B, 1897.)

(No Model.) 2 sheets-sheet 2.

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ROBERT RUFFIN, OF COMO DEPOT, MISSISSIPPI.

DRAFTING INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 614,985, dated November29, 1898.

Application filed August 18, 1897. Serial No. 648,693. (No model.)

.To @ZZ wiz/0m it may concern,.-

Beit known that I, ROBERT RUFFIN, a citizen of the United States,residing at Como Depot, in the county of Panola and State ofMississippi, have invented a new and useful Drafting Instrument, ofwhich the following is a specification.

My invention relates to drafting implements adapted for use in variouslines of drafting, both general, as in mechanical work, and specific, asin geographical and topographical plotting and in the laying off ofmaps, obtaininglatitude and departure, and in various 0perations inconnection with a plane table, and incidentally in the laying off oftimbers in carpentry.

Various objects and advantages of this invention will appear in thefollowing description, and the novel features thereof will beparticularlyT pointed out in the appended claims. p

In the drawings, Figure l is a view of a drafting instrument constructedin accordance with my invention and designed especially for general workin connection with engineering and plotting. Fig. 2 is a detail view inperspective of the slide and the contiguous portion of the adjustable orhypotenuse arm. Fig. 3 is a detail section showing the connectionbetween the adjustable or hypotenuse arm and the iixed perpendicular orlatitudinal arm on line 3 3 of Fig. l. Fig. 4 is a detail sectional viewof the slide and the joint between the same and the adjustable orhypotenuse arm on line 4 4 of Fig. 1. Fig. 5 is a view of a slightlymodified and simpliiied form of the drafting instrument, also adaptedfor general work, but particularly designed for use in practicalcarpentry, for laying off roof and other timbers, ascertaining the pitchand length, as well as the terminal, vertical, and horizontal cutsthereof. Fig. G is a View of another modified form of the instrumentembodying my invention, which is particularly adapted for use inconnection with the plane table in geographical and topographicalplotting.

Similar numerals of reference indicate corresponding parts in all thefigures of the drawings.

In the illustrated embodiment of my invenh tion the essential featuresare a main or lon gitudinal arm carrying a perpendicular fixedlatitudinal arm, an adjustable or hypotenuse arm having a sliding andpivotal connection with the main and perpendicular arms, or one of them,and an angle-gage arranged concentric with a pivotal point of theadjustable or hypotenuse arm, in connection with double verniers foraccurately measuring fractional parts of lines and angles.

The form of instru ment which is illustrated in Figs. l to 4, inclusive,comprises a main or longitudinal arm l, to which is attached or integralwith which is formed a fixed perpendicular or latitudinal arm 2, havinga longitudinal slot 3, whereby the adjustable or hypotenuse arm 4 isadapted, by means of a locking device, such as a clamp 5, for adjustmentat the adjacent end in a direction parallel with said latitudinal arm.The form of clamp illustrated in the drawings consists of a bolt orpivot-pin 6, extendingthrough the slot 3 and a correspondinglongitudinal slot 7 in the adjustable or hypotenuse arm and tted with athumb-nut 8. The slot 7 in the adjustable or hypotenuse arm provides forlinear adjustment of said arm with relation to the Xed perpendicular arm2, and the use of the pivot-pin 6 provides for pivotal movement of theadjustable or hypotenuse arm with relation to the fixed perpendiculararm 2. The opposite end of the adjustable or hypotenuse arm is pivotallyand slidingly mounted upon the main or longitudinal arm l to provide forthe adjustment of the said end of the hypotenuse arm with relation tothe main or longitudinal arm to secure any desired angular position ofthe adjustable arm and any desired lengths of the base, altitude, andhypotenuse of the triangle formed by said main, perpendicular, andadjustable arms. In the construction illustrated the pivotal and slidingconnection between the adjustable arm and the main arm is formed bymeans of a slide 9, fitted for linear adjustment upon the main arm l andhaving an extension or ear lO, (see Fig. 2,) upon which the contiguousextremity of the adjustable arm is pivoted, the slide consisting,essentially, of terminal guide-loops connected by a baseplate ll belowthe plane of the main arm and by a Vernier l2 above and contiguous tothe uppersurface of said main arm. Fur- IOO thermore, the connectionbetween the adjustable arm and the slide consists of a hollow orcentrally-open pivot 13, consisting of an eyelet or any equivalentthereof arranged in such a position with relation to the slide that thefiducial or feather edge of the main arm spans the opening of the hollowpivot and lies accurately above the center thereof, or, in other words,occupies a position in a diametrical plane of the pivot, whereby inapplying the instrument to a line or angle for measurement the center ofthe hollow pivot may be arranged overa given point in sight through thepivot. rlhe center of the hollow pivot is the point at which the inneror operative edge of the adjustable arm t intersects the inner oroperative edge of the main arm. The function of the vernier in thisconnection is too well known to need explanation, it being obvious thatits zero-point is transversely opposite the point of intersection of theoperative edge of the adjustable arm with that of the main arm, or, inother words, is transversely opposite the center of the pivot, and thevernier being of the double type, whereby it may be read in eitherdirection from the zero-point, according to the requirements of themeasurement which is being taken. The base-plate 11, from which the ear10 projects, is spaced from the lower sides of the guideloops oftheslide, as shown in Figs. 2 and 4, to allow the contiguous pivotalextremity of the adjustable arm to operate between the base and theunder surface of the main arm, by means of spacing-blocks 11a.

Carried by the base or other suitable portion of the slide is anangle-gage 14, disposed concentric with the pivot 13 and traversed bythe adjustable arm, by comparison with which angles of detiection of theadjustable arm from the main arm may be measured, said angle -gage inthe construction illustrated consisting of a quadrant-protractor. It isobvious that while the quad rant-protractor only is illustrated in Fig.1 the extension thereof to the ordinary form of semicircular quadrant ispossible without departing from the spirit of the invention, theadvantage of such a modification residing in the fact that other anglesthan those at the base of a right-angled triangle could be measured, thepeculiar construction of clamp which is employed for connecting theadjustable arm to the fixed perpendicular arm providing for thedetachment of the former from the latter, and hence providing forswinging the adjustable arm to a position beyond that of a perpendicularto the main or to a position in which its inclination would be frominstead of toward the fixed arm In the construction which I haveillustrated in Fig. 5 the instrument is simplified by the omission ofthe angle-gage to adapt it particularly for use in practical carpentry,an important function ot' the instrument being in connection with thelaying off of roof-timbers and the equivalents thereof. In theconstruction shown in Fig. 5 the main arm l, slotted perpendicular arm2, adjustable arm 4t, the clamp 5", the slide 9, with its vernierattachment 12, and the pivotal connection 13 between the adjustable armand the slide are equivalent to the corresponding parts described inconnection with Figs. 1 to -l. To give an example of the use of thisform of my invention, let it be supposed that it is required to obtainthe lengt-h of a rafter for a hipped or gable roof having a span ofsixteen feet and a rise or altitude of six feet. As each rafter willextend over a horizontal distance of one-half the span, the slide end ofthe adjustable arm should be arranged to bring the center of the pivotor the zero-point of the vernier over the graduation S of the main arm,(eight feet being one-half the spain) and the opposite cud of theadjustable arm should be adjusted with relation to the perpendicular armto arrange the operative edge of the former at the graduation G of thelatter, whereupon the length of the desired timber-namely, ten feetwillbe indicated on the adjustable arm at its point of intersection with theoperative edge of the perpendicular arm. It' now it is desired to obtainthe bevel of the ends of the rafter cut to the desired length, theinstrument may be used as a bevel and applied to the timber with theadjustable arm parallel therewith. The ed ge of the main arm will givethe line of the horizontal cut of the timber, while the perpendiculararm will give the line of the vertical or perpendicular cut of thetimber.

In the construction which I have illustrated in Fig. G the main arm 1bcarries a slotted, fixed, or perpendicular latitudinal arm 2", which isextended in both directions from the main arm, and an adjustable arm 1h,mounted upon a slide 9, said adjustable arm being preferably duplicated,as indicated, and each adjustable arm having a cooperating semicircularangle-gage 14", carried by the slide. The latitudinal bar 2b ispreferably mounted for sliding movement upon a guide-rib 15, arranged ina iixed position upon the plane table or other surface upon which theinstrument is used and graduated to form a double vernier, said ribhaving terminal clips 1G, which overlap the surface of the latitudinalbar and hold the latter firmly against displacement, while allowingadjustment of said bar parallel with its length. Furthermore, the mainbar or blade 1b is preferably graduated continuously from end to end inopposite directions at its upper and lower edges, respectively, and isalso provided with a central line of graduations having an initial pointat an intermediate part of the bar and being increased in oppositedirections from this central point. This construction, in connectionwith the slide with its vernier 121', enables the operator to plot ineither direction or from a central point in both directions, and henceenables him to obtain the latitude and departure of a line running inany direc- IOO IIO

IIS

tion from either a side or an intermediate initial point. In this formof my invention I preferably provide each adjustable arm with a Vernier17 for use in connection With the angle-gage traversed thereby, and asin geographical and topographical plotting, for which the form ofinstrument illustrated in Fig. 6 is especially design/ed, it isordinarily unnecessary to have the adjustable arm terminally connectedto a perpendicular arm or latitudinal bar I preferably construct theadjustable arm 4l of only sufcient length to extend slightly beyond theperipheries of the angle-gages or protractors.

The operation of either of the forms of my instrument in determining thelatitude and departure of a roof or run will be readily understood bythose familiar with the art, it being obvious that the measurements uponthe perpendicular arm will indicate the latitude and the measurementsupon the main arm the departure When the adjustable arm is arranged toagree with the direction of the line to be measured. In theconstructions illustrated in Figs. 1 to 5, inclusive, it is designed tomeasure latitude and departure by the measurements on the perpendicularand main arms when the adjustable arm is arranged to agree with the run,in which case the length of the run will be indicated upon theadjustable arm; but in the construction illustrated in Fig. 6 it isnecessary in order to obtain the latitude and departure of a line tofirst adjust the slide to arrange the Zeropoint of the Vernier over oneterminal of the line and then slide the instrument upon the guide-rib 15a sufficient distance to bring the operative edge of the main arm to theother terminal of the line, whereupon the distance between thezero-point of the Vernier and the second-named extremity of the lineWill give the departure, While the latitude Will be indicated by thedistance through which the perpendicular arm 2b has been moved, thegraduations thereon being compared With the Vernier on the guide 15.

Furthermore, it Will be understood that While in accurate Work it isdesirable, and in fact necessary, to employ verniers or the equivalentsthereof at the various points indicated, I do not desire to be limitedto the use thereof, as any other suitable indicatingpoints may beemployed when the definite accuracy necessary in close Work in plotting,engineering, die. is not required; and it is obvious,furthermore,thatvarious other changes in the form, proportion, and the minor details ofconstruction may be resorted to Without departing from the spirit orsacrificing any of the advantages of this invention.

Having described my invention, what I claim is- 1. A drafting instrumenthaving a longitudinal bar, a slide mounted for adjustment upon said barand comprisingabase arranged below the plane of the bar, terminalguideloops connected by said base and fitted upon said bar, and adouble-Vernier bar connecting the guide-loops above the plane of thelongitudinal bar, said base being extended to form an ear 10 and anangle-gage 14, and an adjustable arm pivotally mounted upon said ear bymeans of a hollow pivot, of which the center is in the plane of thefiducial edge of said longitudinal bar, substantially as specified.

2. The herein described drafting instrument comprisingperpendicularly-disposed rigidly-connected longitudinal and latitudinalarms 1 and 2, a slide mounted upon the longitudinal arm and havingspaced guideloops connected, contiguous to the plane of the uppersurface of the longitudinal arm, by a Vernier-bar7 said slide carryingan angle-gage, an adjustable or hypotenuse arm pivotally mounted uponsaid slide and intersecting the latitudinal arm, and means for clampingthe hypotenuse and latitudinal arms at their point of intersection, thesaid hypotenuse arm being adjustable longitudinally, laterally, andangularly With relation to the latitudinal arm, substantially asspecified.

In` testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two Witnesses.

ROBERT RUFEIN.

Witnesses:

T. O. HUNTER, Trios. H. TAYLOR.

